227 resultados para Cucumis melo var


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The objective of this work was to study the effect of selective thinning on! the genetic divergence in progenies of Pinus caribaea var. bahamensis, aiming to identify the most productive and divergent progenies for the use of improvement program. The test of progenies containing 119 progenies and two commercial controls were planted in March 1990, using 11 x 11 square lattice design, sextuple, partially balanced, disposed in lineal plots with six trees in the spacing of 3,0 x 3,0m. 13 years after planting thinning was realized (selection for DBH), with 50% selection intensity based on Multi-effect index, leaving three trees per plot in all the experiment. The evaluations were done at four situations: A (before the thinning); B (thinned trees); C (remaining trees after thinning) and D (one year after thinning). The analyzed traits were: height, diameter at breast height (DBH), volume, form of stem and wood density. The genetic divergence among the progenies was studied with aid of the canonical variables and of clustering of Tocher method using the generalized distance matrix of Mahalanobis (D(2)) as estimate of the genetic similarity. The progenies were grouped in four groups in situation A, fourteen in the situation B, two in the situation C and three in the situation D. The selective thinning of the trees within of the progenies caused a change in the genetic divergence among the progenies, genetically homogenizing the progenies, as demonstrated by the generalized distances of Mahalanobis, clustering of Tocher' and canonical variables methods; The. thinning made possible a high uniformity in respect to the relative contribution, of the traits for the total genetic divergence. The techniques, of clustering were efficient to identify groups of divergent,progenies for the use hybridization and little divergent progenies for the use in backcross program.

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The present research has proposed to estimate the genetic variation of growth traits and to estimate the expected gain by multi-effect index (MEI), in order to transform a Pinus caribaea var. caribaea progeny trial into a seedling seed orchard. The progeny trial was set up in 1989, in Selviria, MS, Brazil, using a 10 x 10 triple lattice design, with 99 progenies and a commercial control, with linear plots of ten plants, by the 3 x 3 m spacing between plants and rows. Total plant height, diameter at breast height (Dbh), wood volume, stem form, wood density at breast height, and survival were the evaluated quantitative traits. The trial was measured through 14, 15, and 16 years old. The 50% intensity of thinning at 14.3 years old was done. No significant was the genetic variation of different traits. Heritability estimates have presented low magnitude with low variation by the different ages. The application of MEI to DBH, at two years after thinning, resulted in higher gains than the selection of within and among progenies. The best selection strategy to obtain higher gains and to keep genetic diversity is to select until five plants per progenies.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O trabalho objetivou estudar os efeitos de reguladores vegetais no enraizamento de estacas caulinares de Flying Dragon [Poncirus trifoliata var. monstrosa (T. Ito)]. Na metade de cada estação do ano, ramos de citros foram coletados (4 experimentos), a partir dos quais foram retiradas estacas com 10 cm de comprimento com uma folha cortada ao meio. As bases das estacas foram tratadas com os seguintes reguladores vegetais na forma de talco: Testemunha (H2O); IBA 0,5%; NAA a 0,5%; IBA + ácido caféico a 0,5%, e NAA + ácido caféico 0,5%. As estacas foram plantadas em bandejas de isopor contendo fibra de coco e mantidas por três meses em câmara de nebulização. Os resultados mostraram que para a propagação desta espécie por estaquia, a coleta dos ramos deve ser no outono e que as mesmas sejam tratadas com a mistura de NAA + ácido caféico, ambos a 0,5%.

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The anti-allergic active fractionation of hexane extracts of the leaves and stems of Anchietia salutaris,ar. martiana (family Violaceae) nas performed by monitoring their activities with an in vitro bioassay system measuring the inhibitory effects on induced histamine release from guinea pig lung cells. Three known pentacyclic triterpenes (friedelin, alpha-amyrin, beta-amyrin) were isolated, but these compounds were inactive. Aliphatic hydrocarbons and methyl esters of fatty acids (palmitic, oleic, linoleic, linolenic acids) were detected in active fractions. All compounds isolated were detected for the first time in this medicinal plant.

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Eighty-one lines of cauliflower (Brassica oleracea var. botrytis) from 12 populations used to produce commercial hybrids in Brazil were screened for polymorphism in the acid phosphatase system, in order to evaluate the usefulness of this marker for the determination of the parental contamination level in hybrid seeds. Little polymorphism was detected in the examined lines, but the system appeared to be very useful for hybrid identification, since the only condition required was polymorphism between the two parental lines. If the analyzed lines were used for hybrid production, 8.4% and 12.3% of the possible crosses would result in hybrids which can be positively identified using the APS-1 and B1 loci, respectively. If only one plant of each homozygous type (SS or FF) was analyzed in each population, 41% and 50% of the possible crosses would result in hybrids which can be positively identified using the APS-1 and B1 loci, respectively.

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A ultraestrutura das ectomicorrizas formadas por Pinus caribaea var. hondurensis inoculado com Pisolithus tinctorius (Pers.) Coker & Couch e Telephora terrestris (Ehrenb.) Fr. foi analisada antes do transplantio dessas mudas para o campo, com o intuito de verificar se o fungo estava estabelecido nas raízes. Os fungos ectomicorrízicos inoculados formaram um manto compacto e bem desenvolvido nas raízes laterais. Nas hifas desse manto foram observados vacúolos, núcleos e septos dolipóricos, enquanto que no citoplasma das hifas da rede de Hartig, que ficam adjacentes às células corticais, foram freqüentemente observados vários núcleos, retículo endoplasmático e mitocôndrias polimórficas. Células corticais altamente vacuolizadas, contendo gotículas de material elétron-denso, apresentaram núcleo e algumas organelas na sua estreita região citoplasmática periférica. As ectomicorrizas de P. caribaea var. hondurensis apresentaram características ultraestruturais de uma associação compatível e fisiologicamente ativa.

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The inulinase production by yeast K marxianus var. bulgaricus growing in yacon extract was investigated. The microorganism showed good development in yacon, higher enzymatic activities were achieved at 30% and 40% (v/v) of extract. The cultivation temperature (20, 25, 30, 35, 40 degreesC) neither influenced the growth or the enzymatic activity. The optimum cultivation pH was 3.5. The highest activity was observed at 60 degreesC and pH 4.0. At temperature of 55 C and 60 C occurred sharp decrease in the enzyme activity. (C) 2004 Elsevier Ltd. All rights reserved.

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The crude cell-free medium from a culture of Kluyveromyces marxianus var. bulgaricus was immobilized in a gelatin-water support, with an immobilization yield of 82.60% for inulinase activity. The optimum pH for both free and immobilized inulinase was the same (3.5) and the optimum temperatures were 55 degrees C for the free and 60 degrees C for the immobilized enzyme. The Arrhenius plots were linear and activation energies were 56.20 (free enzyme) and 20.27 kj/mol K (immobilized enzyme). The kinetic parameters were calculated by Lineweaver-Burk plots and the V-max and K-m were 37.60 IU/mg protein and 61.83 mM for the free inulinase and 31.45 IU/mg protein and 149.28 mM for the immobilized enzyme, respectively. The operational stability of the immobilized inulinase was studied in a continuous fixed-bed column reactor for 33 days, at the end of which the sucrose conversion was 58.12%. (c) 2008 Elsevier Ltd. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The anatomy and ultrastructure of root nodules of Anadenanthera peregrina var. falcata (Leguminosae-Mimosoideae) were analysed, as was plant growth. To ensure that nodules developed, seedlings were inoculated with a mixture of six strains of rhizobia. Nodules were produced that differed in appearance-and probably also effectiveness-but their structure was similar and they showed characteristics typical of indeterminate nodules, such as persistent meristematic tissue and a gradient of cells at different stages of development. Many starch grains were present in inner cortex cells and interstitial cells of infected tissue. Infected cells were densely packed with bacteroids, which contained many poly-beta-hydroxybutyrate granules. The high incidence of these granules, together with high levels of starch accumulation in interstitial cells, suggested low N-2-fixation efficiency of the rhizobia isolates used for inoculation. In the symbiosomes of early-senescent infected cells, reticulum-like structures, small vesicles and a fibrillar material were observed; these may be related to bacteroid degradation. In the cytoplasm of late-senescent infected cells, many vesicles and membrane-like structures were observed, probably associated with membrane degradation of bacteroids and peribacteroids. The total biomass of plants inoculated with rhizobia was low and their xylopodia and shoots had low levels of N compared with non-inoculated plants fertilized with ammonium nitrate. However, inoculated plants did not show N-deficiency symptoms and grew better than non-inoculated plants without N fertilization. These growth results, together with ultrastructural observations of nodules, suggest that nitrogen fixation of rhizobia isolates associated with Anadenanthera peregrina var. falcata roots is poor. (C) 2002 Annals of Botany Company.

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Anadenanthera peregrina var. falcata (angico-do-cerrado), uma leguminosa arbórea, forma associações simbióticas com bactérias fixadoras de nitrogênio (rizóbios) e com fungos micorrízicos arbusculares. Com o objetivo de avaliar a eficiência da inoculação de fungos micorrízicos e rizóbios no crescimento inicial de plantas de angico-do-cerrado, crescidas em solo autoclavado e em solo não autoclavado com e sem inoculação, foi desenvolvido um experimento em casa de vegetação, utilizando raízes micorrizadas de milho e uma mistura de isolados de rizóbios como inoculantes. O crescimento das plantas foi influenciado positivamente pela concomitante inoculação do fungo micorrízico e do rizóbio, tendo as plantas desse tratamento apresentado biomassa cerca de 60 % maior do que o controle no décimo mês. A inoculação de apenas um dos microssimbiontes, entretanto, não provocou diferença na produção de biomassa das plantas. A percentagem de colonização micorrízica foi significativamente mais alta e o número de nódulos maior nas raízes das plantas crescidas no solo não autoclavado, ocasionados pela população de fungos e rizóbios nativos. Nesse tratamento, houve pequeno acúmulo de matéria no xilopódio, provavelmente em virtude do dreno fotossintético por parte dos microssimbiontes, e a concentração de P na parte aérea e xilopódio dessas plantas foi cerca de 1,2 e 8 vezes maior, respectivamente, por causa da colonização micorrízica.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)